Low profile electromagnetic relays

ABSTRACT

Low profile electromagnetic relays employing relatively high power, sealed switching units of the &#39;&#39;&#39;&#39;reed&#39;&#39;&#39;&#39; variety that are arranged for normally open contact operation or, when properly biased with a permanent magnet, for normally closed contact operation. Multiple frame and coil sizes accommodate: 1. A normally open contact in the single pole frame. 2. Two normally open contacts or one normally closed contact with the necessary biasing magnet in the two pole frame. 3. Three normally open contacts or one normally open and one normally closed contact with its biasing magnet in the three pole frame.

United States. Patent 1191 Bongard [111 3,845,431 [451 Oct. 29,1974

[ LOW PROFILE ELECTROMAGNETIC RELAYS 52 u.s.c1. 335/152, 335/153 31 1m.c1. 110111 51/28. 58 Field 61 Search 335/151, 152, 153, 154

l References Cited UNITED STATES PATENTS Primary Examiner-R. N. Envall, Jr. Attorney, Agent, or Firm-H. R. Rather; Wm. A. Autio [57] ABSTRACT Low profile electromagnetic relays employing relatively high power, sealed switching units of the reed .variety that are arranged for normally open contact operation or, when properly biased with a permanent magnet, for normally closed contact operation. Multiple frame and coil sizes accommodate:

1. A normally open contact in the single pole frame.

2. Two normally open contacts or one normally closed contact with the necessary biasing magnet in the two pole frame.

. 3,237,096 2/1966 Zechman 335/153 x H Thfee normally p Contacts or one normally 3,522,566 3/1970 Van 116m 335/154 open and one normally closed contact with its J39 biasing magnet in the three pole frame.

9 Claims, 8 Drawing Figures r l r 1 r l n I: I I

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TIIIIIIIITHIIIIIIII H II Illlllll lllllllllllill lllllllllllllllllj BACKGROUND OF THE INVENTION Relays which employ sealed reed type contact mechanisms have been known heretofore. However, these prior relays were limited to the control of relatively low power (50 to I VA nonarcing loads) in orderto achieve the long reliable life that has come to be expected of a reed type relay.

The relays disclosed here concern improvements thereover.

SUMMARY OF TI-IEINVENTION This invention relates to reed type relays of the embedded, low profile type. These relays employ the improved high power" sealed switching units disclosed in J. A. Bongard et al. US. Pat. No. 3,327,262, dated June 20, I967, in unique relay configurations which optimize power input requirements and overall size by balancing the volume of coil copper wth the judicious use of iron to direct the magnetic flux to the working gap of the relay switch or switches to achieve proper relay operation and employs the coil bobbin as the basic member around which other relay members are assembled and interlocked to accomplish a coherent structure which is ultimately encapsulated in epoxy.

An object of the invention is to provide improved power" reed type relays.

A more specific object of the invention is to provide an improved series of reed type relays which can be --used in the output stage of most semi-conductor logic circuits because of the low driving power requirements and whose normally open and/or normally closed contacts are capable of switching relatively large loads such as the operating coils of large contactors or solenoids thereby eliminating the need for an interposing relay.

Another specific object of the invention is to provide a series of reed type relays of a size that are-mountable on printed circuit (PC) boards and incorporate coil bobbins which vary in size to accommodate multiple switching units and which also serve as the basic structural members of the-relays around which a unique combination of interlocking parts (iron for magnetic purposes and thermoplastic for electrical insulation and structural assembly) provide a coherent structure for ultimate encapsulation in cast resin.

Another specific object of the invention is to provide a second series of reed type relays which can be used in the output stage of most semi-conductor logic circuits because the driving power is lower than the first series of relays but is limited to normally open contacts which are capable of switching relatively large loads such as the operating coils of large contactors or solenoids thereby eliminating the need for interposing relays.

Another specific object of the invention is to provide a second series of reed type relays of a size that is smaller than the first series and is mountable on PC mountingtechnique and incorporating coil bobbinswhich vary insize to accommodate multiple switching units and which also serve as the basic structural members of the relays around which a,unique combination thermoplastic for electrical insulation and structural assembly) provide a coherent structure for ultimate encapsulation in cast resin.

Other objects and advantages of the invention will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an enlarged cross-sectional plan view of a magnetically-shielded reed type relay having three normally-open contact poles taken along line I-I of FIG.

FIG. 2 is a cross-sectional side view taken along line 22 of FIG. 1;

FIG. 3 is an enlarged cross-sectional plan view like FIG. 1 of a relay having a normally-open contact pole and a normally-closed contact pole;

FIG. 4 is a cross-sectional end view taken along line 4-4 of FIGf3; and

FIG. 5 is an end view of a magnet frame used in the reed relay of FIGS. 1-4.

FIG. 6 is an enlarged cross-sectional side view of a single-pole, normally-open contact, unshielded reed type relay taken along line 6-6 of FIG. 7;

FIG. 7 is a right-hand end view of the reed relay of FIG. 6; and

FIG. 8 is an enlarged plan view of the relay of FIGS. 6-7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, there is shown a threepole normally-open contact relay constructed in accordance with the invention. This relay comprises an insulatingbobbin 2 on which is wound an operating coil 4. The bobbin is provided with three slots for accommodating three encapsulated switches 6, 8 and 10, respectively, therein. A U-shaped magnetic frame 12 embraces the bobbin and coil, and tubular magnetic core poles 14 and 16 are mechanically assembled to and extend from arms 12a and 12b thereof and surround opposite end portions of switch 6. In a similar manner, tubular core poles l8 and 20 extend from opposite arms 12a and 12b of themagnetic frame and around the opposite end portions of switch 8. And similarly, core poles 22 and 24 extend from the opposite arms of magnetic frame 12 into surrounding relation with the opposite end portions of switch 10.

For supporting the three tubular core poles, each arm 12a and I2!) of magnetic frame 12 is provided with an elongated aperture as shown in FIG. 5. This aperture is provided with three enlarged, circular sections 12c, 12d and 12a for locating the associated tubular core poles and into which the latter are inserted up to their shoulders or end flanges 22a and 240, etc., resulting in a mechanical interference fit as shown in FIG. 2.

A pair of resilient plugs 26 and 28 are inserted into the outer ends of tubular core poles l4 and I6, respectively, to retain and axially orient switch 6 within its slot. In a similar manner, plugs 30 and 32 are inserted in the outer ends of tubular core poles l8 and 20 to retain switch 8 within its slot and keep it from sliding out. And likewise, plugs 34 and 36 are pressed into the outer ends of magnetic core poles 22 and 24 to retain switch 10 within its slot.

As shown in FIGS. 1, 2 and 3 and further clarified in FIG. 4, bobbin 2 may be a molded plastic member having an appropriately shaped core configuration such that a switch 38 with its assembled biasing magnet structure 40 or two switches S and 10, may be assembled in the two pole positions closest to the base of the U-shaped magnet frame 12, and the third pole position located farthest from the base of the U-shaped magnet frame 12 willonly accommodate a single switch 6 because of the molded section 2a.

Contact operating coil 4 is wound around this switch accommodating portion (core) of the bobbin and between molded flanges 2b and 20 at its opposite ends. The outer surfaces of these flanges are provided with suitable shoulders for slidably receiving from one side the pair of arms 12a and 12b of magnetic frame 12. The inner surfaces of these flanges are provided with suitable shoulders for slidably receiving from the other side the skirts 42a and 42b of a generally U-shaped sheet steel, magnetic shield 42 shown in FIG. 4.

In addition, the bobbin provides terminal supports and locating means in the form of integrally molded lateral plates or extensions 2d and 2e at its left and right ends, respectively. Terminal pins made from appropriate material are inserted vertically through tapered holes in these lateral sections and are securely held therein as a result of the interference fit which exists on one end of the tapered hole. These securely located pins are then used in conjunction with the vertical extensions on the bobbin flange to properly positionthe relay in the mold when it is to be embedded in a cast resin 56 as indicated by the broken line.

The terminal pins include a pair of pins 44 and 45 to which the ends of the operating coil are electrically connected and additional pairs of pins 46-47, 48-49 and 50-51 that are soldered or welded to the terminals of their respective switches.

A pair of holes 52 and 54 are provided in the lateral extensions 2d and 2e, respectively, to establish clearance for the mounting holes 53 and 55 that are molded in the cast resin 56 as part of the encapsulating process and which can be used to augment the solder connections between the terminal pins and the PC board which conventionally are also used for mechanically mounting PC board components. I

As shown in FIGS. 1 and 2, each insulating plug such as 26 is provided with a slit or rectangular hole in its capped end through which the terminal of the switch extends. Each such plug is also provided with a tubular portion which has two diametrically opposite shallow semi-spherical segments on its outer surface such that when it is inserted within the end of its associated tubular core pole a secure assembly results. Each such plug is further provided with a short flange that abuts the end of the tubular core pole and provides positive position control of the switching element as shown in FIGS. 1 and 2.

As shown in FIGS. 1-3, tubular core poles of two different lengths are provided to accommodate the particular switch structure. As seen in FIG. 1, left hand tubular core pole 14 is longer than right hand tubular core pole 16 in order to concentrate the magnetic flux in the area of the switch magnetic gap, this gap being located V to the right of the center of the switch.

shown in FIGS. 3 and 4, this magnet 40 is comprised of a pair of spaced permanet magnets 40a and 40!) made of ALNICO Vlll material or the like and connected by plate 400 made of magnetic material which is rigidly secured along one side of the pemianent magnets, a sleeve 40d made of magnetic material rigidly secured to the opposite surface of permanent magnet 40a and another sleeve 40c made of magnetic material rigidly secured to the opposite surface of permanent magnet 40b. Left hand sleeve 40d is longer than righthand sleeve 40 and the two sleeves are aligned to allow insertion of the switch through the sleeves for concentrating the magnetic flux in the area of the magnetic gap. These sleeves are cemented onto the glass envelope of the switch to form a unitary structure having an established relationship between the permanent magnet and the magnetic gap of the switch that can be separately calibrated for proper switch operation before insertion into a double slot in the bobbin. This unitary structure is then positively positioned in the relay by a pair of double plugs 58 and 60 which are inserted in the apertures in the magnetic frame as can be seen in FIG. 3.

The double plugs 58 and 60 serve the same purposes as plugs 26 and 28 previously described and as such each plug is provided with two tubular portions which have two diametrically opposite shallow semi-spherical segments on their outside surfaces such that when they are inserted in frame 12, a secure assembly results. Each such plug is further provided with a short flange that abuts the-frame to achieve positive positioning of the switch. 2 g

A single pole unshielded version of the relay series, characterized by smaller size and lower power requirements but also limited to normally open switching functions, is represented by FIGS, 6-8. This version has an insulating bobbin 62 on which is would an operating coil 64 which is connected to a pair of terminals 66 and 67 shown in FIG. 8. These terminals are mounted at one end thereof by means of an interference fit in slots provided in bosses 62a and 62b that extend laterally from the bobbin flanges.

A U-shaped magnetic frame 68 slides onto the bobbin so that the apertures in its arms line up with the stepped bore in the bobbin. A pair of tubular core poles 70 and 72 are then press fitted into the apertures in the frame to a dimension determined by the stepped bore in the bobbin to retain the frame on the bobbin and to position the concentration of magnetic flux in the area of the switch magnet gap. A switch 74 is then inserted into the bore of the core poles, and insulating plugs 76 and 78, each having a slit for a switch terminal, are pressed over the external ends of the tubular core poles to positively position the switching unit and provide a coherent assembly for encapsulation in cast resin. First ends of terminal pins 80 and 82 are then soldered or welded to the switch terminals. The other ends of these terminals as well as coil terminals 66 and 67 are normally provided as represented by 80a and 82a in FIG. 6 for axial type connection of the relay or can be shaped as represented by 80 and 82 in FIG. 6 for conventional PC board connection which, when employed, has the advantage that all of the relay terminals are accessible for tests purposes on both sides of the PC board.

Mounting holes 83 and as shown in FIG. 8 are molded in the cast resin 84 as part of the encapsulation process to provide a positive mounting means when the aforementioned axial type of connection is used or to augment the conventional PC board mounting.

The positive positioning of the terminals in this relay series is established by the molding die and the proper positioning of the relay in the molding die is established by the molding bosses 62a-62f and the lateral extensions from the bobbin flange from which bosses 62c-62f extend.

While athree-pole shielded version of the relay has been shown in H68. 1 and 2 and specifically described, and a single-pole unshielded version of the relay has been shown in FlGS. 6-8 and specifically described, it will be apparent that shielded versions containing other pole combinations and numbers of poles can be constructed in a manner similar to that shown in FIGS. 1 and 2. These versions would have some parts common to the three-pole version and would differ therefrom in that the bobbin would have an appropriately shaped slot, the magnetic frame would have a length suited to the bobbin as would the magnet shield skirt. The twopole shielded version could be used for two normallyopen switches or for a normally-closed switch and bias magnet as shown in FIGS. 3 and 4. Multipole versions of the single-pole relay shown in FIGS. 6-8 and specifically described could also be constructed by employing some common parts and extending the magnet frame and bobbin to accommodate-more switches.

While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiments of the relays disclosed, inasmuch as they are susceptible of various modifications without departing from the scope of the appended claims.

I claim:

l. A low profile encapsulated relay comprising:

a coil bobbin of insulating material having a bore therethrough;

a coil wound on said bobbin;

a U-shaped magnetic frame having apertures in its arms corresponding to the endsof saidbore;

shoulders at the ends of said bobbin providing.

grooves to slidably receive and retain the arms of said magnetic frame'so that the apertures therein register with said bore;

tubular core poles extending through said apertures to retain said frame on said bobbin and to establish the position of a concentration of magnetic flux;

a sealed switching unit coaxially located within said core poles so that the magnetic gap of the switching unit is located in said concentration of magnetic flux;

resilient plugs at the ends of said core poles for retaining and fixing the position of said switching unit in said core poles and thereby also fixing said magnetic gap of the switching unit in said concentration of magnetic flux and having holes through which the switching unit terminals extend and are located;

a first pair of terminals having said coil connected thereacross;

means mounting said first pair of terminals to said bobbin;

a second pair of terminals connected to the terminals of said switchingunit;

and said relay being embedded in casting material with the ends of said pairs of terminals exposed for making connection thereto and mounting means in the form of two holes case in the embedding material.

2. The relay defined in claim 1, wherein said bobbin is provided with a plurality of bores therethrough. said U-shaped magnetic frame is provided with increased depth having in its arms a plurality of apertures in registration with the respective bores in said bobbin. and said bores and apertures having associated tubular core poles and plugs to accommodate a plurality of adjacently mounted sealed switching units therein with their terminals extending out through the holes in said plugs.

3. The relay defined in claim 1., wherein said bobbin is provided with two bores therethrough with an elongated opening between said bores and said U-shaped magnetic frame is provided with apertures in its arms in registration with the ends of said bores;

said sealed switching unit and its associated tubular core poles being located in the bore adjacent the base of said U--shaped magnetic frame;

a permanent magnet located in the remaining bore and means physically attaching said magnet to said switching unit, and said magnet being magnetically oriented to cause said switching unit to close under normal conditions and to open when said coil is energized with the proper polarization;

and resilient plugs located at the ends of said switch ing unit and engaging said switching unit and said U-shaped magnetic frame for proper positioning thereof.

4. The relay defined in claim 1, wherein said bobbin is provided with three bores therethrough with an elongated opening between the first and second bores adjacent the base of said U-shaped magnetic frame, and said U-shaped magnetic frame is provided in its arms with apertures in registration with the ends of said bores:

sealed switching units located in the bores adjacent to and farthest from the base of said U-shaped magnetic frame; V

a permanent magnet located in the center bore and means physically attaching said magnet to said switching unit adjacent the base of said U-shaped magnetic frame, and said magnetbeing magnetically oriented to cause said switching unit to close under normal conditions and to open when said coil .is energized with the proper polarization;

and resilient plugs located at the ends of said switching units and engaging said switching units and said U-shaped magnetic frame for proper positioning thereof.

5. The relay defined in claim I, wherein said means mounting said first pair of terminals to said bobbin comprises:

lateral plate extensions on the ends of said bobbin for supporting the first pair of coil terminals and the second pair of switching unit terminals which extend therethrough and are rigidly held therein.

6. The relay defined in claim 1, wherein:

said bobbin comprises flanges at its opposite ends with said magnetic frame retaining shoulders being on the outer sides of said flanges;

together with a U-shaped magnetic shield;

and inner shoulders on the inner sides of said flanges adapted to slidably receive and retain the skirts of said magnetic shield to enclose said coil on all sides not covered by said magnetic frame.

7. The relay defined in claim 1, wherein:

said core poles are shouldered to positively position one with respect to the other;

each said resilient plug having a tubular portion, a

shoulder, and two diametrically opposite shallow semi-spherical bosses on the outer surface thereof to engage the core pole and provide positive posi tioning and entrapment of the sealed switching unit therein;

and said terminal pairs being arranged to extend vertically from the base of the embedded relay.

8. The relay defined in claim 3, wherein said permanent magnet and its attaching means comprises:

axial assembly thereof into said axially aligned pole piece sleeves;

said resilient plugs having two adjacent tubular portions, each having a shoulder and two diametrically opposite shallow semi-spherical bosses on the outer surface of each tubular portion to provide positive positioning of the sealed switching unit and permanent magnet subassembly within said U-shaped magnetic frame by means of an interference fit therebetween;

and said terminal pairs being arranged to extend vertically from the base of the embedded relay.

9. The relay defined in claim 1, wherein:

said bore in said bobbin is stepped to provide positive positioning of said tubular core poles;

said resilient plugs being shaped to bottom over said tubular core poles and having a tubular section provided with two diametrically opposite shallow semi-spherical bosses on the inner surface thereof to afford positive postioning and entrapment of said switching unit within said core poles and an interference fit between said U-shaped magnetic frame and said plugs;

and the terminal pairs being arranged to extend vertically from opposite ends of the embedded relay. 

1. A low profile encapsulated relay comprising: a coil bobbin of insulating material having a bore therethrough; a coil wound on said bobbin; a U-shaped magnetic frame having apertures in its arms corresponding to the ends of said bore; shoulders at the ends of said bobbin providing grooves to slidably receive and retain the arms of said magnetic frame so that the apertures therein register with said bore; tubular core poles extending through said apertures to retain said frame on said bobbin and to establish the position of a concentration of magnetic flux; a sealed switching unit coaxially located within said core poles so that the magnetic gap of the switching unit is located in said concentration of magnetic flux; resilient plugs at the ends of said core poles for retaining and fixing the position of said switching unit in said core poles and thereby also fixing said magnetic gap of the switching unit in said concentration of magnetic flux and having holes through which the switching unit terminals extend and are located; a first pair of terminals having said coil connected thereacross; means mounting said first pair of terminals to said bobbin; a second pair of terminals connected to the terminals of said switching unit; and said relay being embedded in casting material with the ends of said pairs of terminals exposed for making connection thereto and mounting means in the form of two holes case in the embedding material.
 2. The relay defined in claim 1, wherein said bobbin is provided with a plurality of bores therethrough, said U-shaped magnetic frame is provided with increased depth having in its arms a plurality of apertures in registration with the respective bores in said bobbin, and said bores and apertures having associated tubular core poles and plugs to accommodate a plurality of adjacently mounted sealed switching units therein with their terminals extending out through the holes in said plugs.
 3. The relay defined in claim 1, wherein said bobbin is provided with two bores therethrough with an elongated opening between said bores and said U-shaped magnetic frame is provided with apertures in its arms in registration with the ends of said bores; said sealed switching unit and its associated tubular core poles being located in the bore adjacent the base of said U-shaped magnetic frame; a permanent magnet located in the remaining bore and means physically attaching said magnet to said switching unit, and said magnet being magnetically oriented to cause said switching unit to close under normal conditions and to open when said coil is energized with the proper polarization; and resilient plugs located at the ends of said switching unit and engaging said switching unit and said U-shaped magnetic frame for proper positioning thereof.
 4. The relay defined in claim 1, wherein said bobbin is provided with three bores therethrough with an elongated opening between the first and second bores adjacent the base of said U-shaped magnetic frame, and said U-shaped magnetic frame is provided in its arms with apertures in registration with the ends of said bores: sealed switching units located in the bores adjacent to and farthest from the base of said U-shaped magnetic frame; a permanent magnet located in the center bore and means physically attaching said magnet to said switching unit adjacent the base of said U-shaped magnetic frame, and said magnet being magnetically oriented to cause said switching unit to close under normal conditions and to open when said coil is energized with the proper polarization; and resilient plugs located at the ends of said switching units and engaging said switching units and said U-shaped magnetic frame for proper positioning thereof.
 5. The relay defined in claim 1, wherein said means mounting said first pair of terminals to said bobbin comprises: lateral plate extensions on the ends of said bobbin for supporting the first pair of coil terminals and the second pair of switching unit terminals which extend therethrough and are rigidly held therein.
 6. The relay defined in claim 1, wherein: said bobbin comprises flanges at its opposite ends with said magnetic frame retaining shoulders being on the outer sides of said flanges; together with a U-shaped magnetic shield; and inner shoulders on the inner sides of said flanges adapted to slidably receive and retain the skirts of said magnetic shield to enclose said coil on all sides not covered by said magnetic frame.
 7. The relay defined in claim 1, wherein: said core poles are shouldered to positively position one with respect to the other; each said resilient plug having a tubular portion, a shoulder, and two diametrically opposite shallow semi-spherical bosses on the outer surface thereof to engage the core pole and provide positive positioning and entrapment of the sealed switching unit therein; and said terminal pairs being arranged to extend vertically from the base of the embedded relay.
 8. The relay defined in claim 3, wherein said permanent magnet and its attaching means comprises: a pair of permanent magnet members and a short strip of magnetic material to one side of which said permanent magnet members are secured in spaced apart relation; two pole piece sleeves of cylindrical shape and magnetic material secured to the opposite surface of said respective permanent magnet members in axially aligned spaced apart relation, said sealed switching unit being tubular shaped to permit the axial assembly thereof into said axially aligned pole piece sleeves; said resilient plugs having two adjacent tubular portions, each having a shoulder and two diametrically opposite shallow semi-spherical bosses on the outer surface of each tubular portion to provide positive positioning of the sealed switching unit and permanent magnet subassembly within said U-shaped magnetic frame by means of an interference fit therebetween; and said terminal pairs being arranged to extend vertically from the base of the embedded relay.
 9. The relay defined in claim 1, wherein: said bore in said bobbin is stepped to provide positive positioning of said tubular core poles; said resilient plugs being shaped to bottom over said tubular core poles and having a tubular section provided with two diametrically opposite shallow semi-spherical bosses on the inner surface thereof to afford positive postioning and entrapment of said switching unit within said core poles and an interference fit between said U-shaped magnetic frame and said plugs; and the terminal pairs being arranged to extend vertically from opposite ends of the embedded relay. 